LT5515
1.5GHz to 2.5GHz
Direct Conversion
Quadrature Demodulator
FEATURES
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DESCRIPTIO
Frequency Range: 1.5GHz to 2.5GHz
High IIP3: 20dBm at 1.9GHz
High IIP2: 51dBm at 1.9GHz
Noise Figure: 16.8dB at 1.9GHz
Conversion Gain: –0.7dB at 1.9GHz
I/Q Gain Mismatch: 0.3dB
I/Q Phase Mismatch: 1°
Shutdown Mode
16-Lead QFN 4mm
×
4mm Package
with Exposed Pad
The LT
®
5515 is a 1.5GHz to 2.5GHz direct conversion
quadrature demodulator optimized for high linearity re-
ceiver applications. It is suitable for communications
receivers where an RF signal is directly converted into I
and Q baseband signals with bandwidth up to 260MHz.
The LT5515 incorporates balanced I and Q mixers, LO
buffer amplifiers and a precision, high frequency quadra-
ture generator.
In an RF receiver, the high linearity of the LT5515 provides
excellent spur-free dynamic range, even with fixed gain
front end amplification. This direct conversion receiver
can eliminate the need for intermediate frequency (IF)
signal processing, as well as the corresponding require-
ments for image filtering and IF filtering. Channel filtering
can be performed directly at the outputs of the I and Q
channels. These outputs can interface directly to channel-
select filters (LPFs) or to a baseband amplifier.
LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
APPLICATIO S
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Cellular/PCS/UMTS Infrastructure
High Linearity Direct Conversion I/Q Receiver
High Linearity I/Q Demodulator
RF Power Amplifier Linearization
TYPICAL APPLICATIO
5V
BPF
LNA
BPF
RF
+
V
CC
LT5515
I
OUT
I
OUT
+
LPF
P
OUT
, IM2, IM3 (dBm/TONE)
VGA
–
RF
–
LO
+
0°
DSP
LO INPUT
Q
OUT+
0°/90°
LO
–
ENABLE
EN
90°
Q
OUT–
LPF
VGA
5515 F01
Figure 1. High Signal-Level I/Q Demodulator for Wireless Infrastructure
U
I/Q Output Power, IM2, IM3
vs RF Input Power
20
0
P
OUT
– 20
IM3
– 40
IM2
– 60
– 80
–100
–16
T
A
= 25°C
P
LO
= –5dBm
f
LO
= 1901MHz
f
RF1
= 1899.9MHz
f
RF2
= 1900.1MHz
–12
–8
–4
0
RF INPUT POWER (dBm)
4
8
5515 • TA01
U
U
5515fa
1
LT5515
ABSOLUTE
(Note 1)
AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
TOP VIEW
Power Supply Voltage ............................................ 5.5V
Enable Voltage ...................................................... 0, V
CC
LO
+
to LO
–
Differential Voltage ...............................
±2V
(+10dBm Equivalent)
RF
+
to RF
–
Differential Voltage ................................
±2V
(+10dBm Equivalent)
Operating Ambient Temperature ..............–40°C to 85°C
Storage Temperature Range ................. – 65°C to 125°C
Maximum Junction Temperature .......................... 125°C
ORDER PART
NUMBER
12 V
CC
Q
OUT +
16 15 14 13
GND 1
RF
+
2
RF
–
Q
OUT –
I
OUT +
I
OUT –
LT5515EUF
3
17
11 LO
–
10 LO
+
9
V
CC
GND 4
5
6
7
8
V
CM
V
CC
UF PACKAGE
16-LEAD (4mm
×
4mm) PLASTIC QFN
EXPOSED PAD (PIN 17) IS GND,
MUST BE SOLDERED TO PCB
T
JMAX
= 125°C,
θ
JA
= 38°C/W
V
CC
UF PART
MARKING
5515
Order Options
Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking:
http://www.linear.com/leadfree/
Consult LTC Marketing for parts specified with wider operating temperature ranges.
AC ELECTRICAL CHARACTERISTICS
PARAMETER
Frequency Range
LO Power
Conversion Gain
Noise Figure
Input 3rd Order Intercept
Input 2nd Order Intercept
Input 1dB Compression
Baseband Bandwidth
I/Q Gain Mismatch
I/Q Phase Mismatch
Output Impedance
LO to RF Leakage
RF to LO Isolation
(Note 4)
(Note 4)
Differential
CONDITIONS
T
A
= 25°C. V
CC
= 5V, f
RF1
= 1899.9MHz, f
RF2
= 1900.1MHz,
f
LO
= 1901MHz, P
LO
= –5dBm unless otherwise noted. (Notes 2, 3) (Test circuit shown in Figure 2)
MIN
TYP
1.5 to 2.5
–10 to 0
Voltage Gain, Load Impedance = 1k
2-Tone, –10dBm/Tone,
∆f
= 200kHz
2-Tone, –10dBm/Tone,
∆f
= 200kHz
–3
–0.7
16.8
20
51
9
260
0.3
1
120
– 46
46
0.7
MAX
UNITS
GHz
dBm
dB
dB
dBm
dBm
dBm
MHz
dB
deg
Ω
dBm
dB
EN
5515fa
2
U
W
U
U
W W
W
LT5515
DC ELECTRICAL CHARACTERISTICS
PARAMETER
Supply Voltage
Supply Current
Shutdown Current
Turn-On Time
Turn-Off Time
EN = High (On)
EN = Low (Off)
EN Input Current
Output DC Offset Voltage
(
⏐
I
OUT+
– I
OUT–
⏐
,
⏐
Q
OUT+
– Q
OUT–
⏐
)
Output DC Offset Variation vs Temperature
V
ENABLE
= 5V
EN = Low
CONDITIONS
T
A
= 25°C. V
CC
= 5V unless otherwise noted.
MIN
4
95
125
120
650
1.6
1.3
2
4
30
25
TYP
MAX
5.25
160
20
UNITS
V
mA
µA
ns
ns
V
V
µA
mV
µV/°C
f
LO
= 1901MHz, P
LO
= –5dBm
– 40°C to 85°C
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2:
Tests are performed as shown in the configuration of Figure 2 with
R1 = 8.2Ω, unless otherwise noted.
Note 3:
Specifications over the – 40°C to 85°C temperature range are
assured by design, characterization and correlation with statistical process
control.
Note 4:
Measured at P
RF
= –5dBm and output frequency = 1MHz.
5515fa
3
LT5515
TYPICAL PERFOR A CE CHARACTERISTICS
(Test circuit optimized for 1.9GHz operation as shown in Figure 2)
Conv Gain, NF, IIP3 vs
RF Input Frequency
25
IIP3
150
SUPPLY CURRENT (mA)
T
A
= 85°C
130
T
A
= 25°C
110
T
A
= – 40°C
90
GAIN (dB), NF (dB), IIP3 (dBm)
20
NF
15
10
5
0
CONV GAIN
70
4.0
4.5
5.0
SUPPLY VOLTAGE (V)
5.5
5515 ¥ G01
Supply Current vs Supply Voltage
170
P
LO
= –5dBm
T
A
= 25°C
V
CC
= 5V
IIP2 (dBm)
I/Q Output Power, IM3 vs
RF Input Power
20
0
P
OUT
, IM3 (dBm/TONE)
–20
T
A
= – 40°C
–40
T
A
= 25°C
–60
–80
–100
–16
T
A
= 85°C
f
LO
= 1901MHz
V
CC
= 5V
OUTPUT POWER
1.0
GAIN MISMATCH (dB)
IM3
1.4
T
A
= 85°C
0.6
T
A
= 25°C
T
A
= – 40°C
0.2
PHASE MISMATCH (DEG)
–12
–8
–4
0
RF INPUT POWER (dBm)
Conv Gain, IIP3 vs
Supply Voltage
24
20
CONV GAIN (dB), IIP3 (dBm)
16
12
8
4
0
–4
4.0
T
A
= 85°C
4.5
5.0
SUPPLY VOLTAGE (V)
5.5
5515 ¥ G07
IIP3
T
A
= 85°C
T
A
= 25°C
CONV GAIN (dB), IIP3 (dBm)
T
A
= – 40°C
18
f
RF
= 1.7GHz
f
RF
= 1.9GHz
16
f
RF
= 2.1GHz
20
16
12
8
4
f
LO
= 1901MHz
P
LO
= –5dBm
T
A
= 25°C
CONV GAIN
T
A
= – 40°C
NF (dB)
4
U W
4
8
5515 ¥ G04
IIP2 vs RF Input Frequency
70
P
LO
= –5dBm
T
A
= 25°C
V
CC
= 5V
60
50
40
30
–5
1.7
1.8
2.3
2.2
1.9 2.0 2.1
RF INPUT FREQUENCY (GHz)
2.4
20
1.7
1.8
2.3
1.9 2.0 2.1 2.2
RF INPUT FREQUENCY (GHz)
2.4
5515 ¥ G02
5515 ¥ G03
I/Q Gain Mismatch vs
RF Input Frequency
6
f
BB
= 1MHz
P
LO
= –5dBm
V
CC
= 5V
4
2
0
–2
–4
I/Q Phase Mismatch vs
RF Input Frequency
f
BB
= 1MHz
P
LO
= –5dBm
T
A
= 85°C
T
A
= 25°C
T
A
= – 40°C
– 0.2
– 0.6
1.7
1.8
1.9 2.0 2.1
2.2 2.3
RF INPUT FREQUENCY (GHz)
2.4
–6
1.7
1.8
2.3
2.2
1.9 2.0 2.1
RF INPUT FREQUENCY (GHz)
2.4
5515 ¥ G05
5515 ¥ G06
NF vs LO Input Power
20
24
Conv Gain, IIP3 vs
LO Input Power
IIP3
T
A
= 25°C
T
A
= – 40°C
T
A
= 85°C
f
LO
= 1901MHz
V
CC
= 5V
T
A
= 25°C
T
A
= – 40°C
T
A
= 85°C
–10
–8
–6
–4
–2
LO INPUT POWER (dBm)
0
14
T
A
= 25°C
V
CC
= 5V
12
–12
–10
–2
–8
–6
–4
LO INPUT POWER (dBm)
0
CONV GAIN
0
–4
–12
5515 ¥ G08
5515 ¥ G09
5515fa
LT5515
TYPICAL PERFOR A CE CHARACTERISTICS
(Test circuit optimized for 1.9GHz operation as shown in Figure 2)
LO-RF Leakage vs
LO Input Power
–40
T
A
= 25°C
V
CC
= 5V
LO-RF LEAKAGE (dBm)
f
RF
= 1.9GHz
f
RF
= 2.2GHz
–50
f
RF
= 2.4GHz
–55
f
RF
= 1.7GHz
RF-LO ISOLATION (dB)
–45
80
70
60
50
40
30
–60
–12
20
–15
f
RF
= 1.7GHz
IIP2 vs LO Input Power
70
f
LO
= 1901MHz
V
CC
= 5V
65
60
IIP2 (dBm)
55
50
45
40
35
30
–10
–8
–2
–4
LO INPUT POWER (dBm)
–6
0
5515 ¥ G10
T
A
= – 40°C
T
A
= 25°C
T
A
= 85°C
RF, LO Port Return Loss vs
Frequency
0
2
0
–5
RETURN LOSS (dB)
CONV GAIN (dB)
–2
GAIN (dB), NF (dB), IIP3 (dBm)
–10
RF
LO
–15
–20
1.5
2.5
2.0
FREQUENCY (GHz)
SUPPLY CURRENT (mA), IIP2 (dBm)
U W
3.0
5515 ¥ G13
RF-LO Isolation vs
RF Input Power
T
A
= 25°C
V
CC
= 5V
f
RF
= 2.4GHz
f
RF
= 2.2GHz
f
RF
= 1.9GHz
–10
–8
–6
–4
–2
LO INPUT POWER (dBm)
0
–10
–5
0
5
RF INPUT POWER (dBm)
10
5515 ¥ G12
5515 ¥ G11
Conv Gain vs
Baseband Frequency
25
Conv Gain, NF, IIP3 vs R1
IIP3
f
LO
= 1901MHz
P
LO
= –5dBm
T
A
= 25°C
V
CC
= 5V
T
A
= – 40°C
T
A
= 25°C
T
A
= 85°C
20
15
10
5
0
–5
CONV GAIN
NF
–4
–6
f
LO
= 1.9GHz
V
CC
= 5V
0.1
10
1
100
BASEBAND FREQUENCY (MHz)
1000
5515 ¥ G14
–8
2
3
4
5
6
7
R1 (Ω)
8
9
10
5515 ¥ G15
Supply Current, IIP2 vs R1
150
130
110
SUPPLY CURRENT
f
LO
= 1901MHz
P
LO
= –5dBm
90
T
A
= 25°C
V
CC
= 5V
70
50
30
IIP2
2
3
4
5
6
7
R1 (Ω)
8
9
10
5515 ¥ G16
5515fa
5
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